High strength epoxy resins prepared from epichlorohydrin and xylylene glycols



United States Patent "ice 3,477,966

Patented Nov. 11, 1969 3,477,966 Broadly, a Lewis acid catalyst can be defined as an elec- HIGH STRENGTH EPOXY RESINS PREPARED tron pair acceptor. Suitable condensation catalysts of this FRO EPICHLOROHYDRIN AND XYLYLENE type include hydrofluoric acid, stannic chloride, ferric GLYCOLS chloride, aluminum chloride, boron trifluoride and com- Richard C. Doss, Bartlesville, 0kla., assignor to Phillips plexes of boron trifluoride, especially its complex with v Petroleum Company, a corporation of Delaware 5 ether. The concentration of the catalyst employed can No Drlavgmcgi 333019626, Ser. No. 596, vary, depending upon the catalyst and the molecular Us. CL 2 g I /0 3/165 Claims weight of the polymer desired. In general, the catalyst can be employed in amounts varying from about 0.1 percent to about 5 percent by weight of the reactants. ABSTRACT OF THE DISCLOSURE The epihalohydrin is employed in an amount suflicient to provide at least four mols of epihalohydrm per mol of A new P Y IeSlIl p p from eplchlofohydl'lu and the xylylene glycol. A suitable molar ratio of epihalohydrin y y q s y and cured products therefrom useful as to xylylene glycol is, for example, from 4 to s, or more. adhesives. Best results are obtained when the epihalohydrin is added slowly throughout the course of the reaction. Care should This in ti relates to novel hi h strength epoxy be taken that these materials react continuously and do r i not accumulate in the reaction mixture is unconverted In one aspe t, th i ti l t t novel epoxy form because otherwise a violent reaction can result. resins which form adhesives of high strength, and which The temperatures used in the condensation a i n have the general formul can vary over a wide range. In general, the temperatures C2 CHCH2 -E0 (EH-011210011 HZO OHPCH O -CI:[2-O H--CH2 L In L I:

wherein n is an integer of at least 1, preferably 1-3. can be in the range of from about 0 to about In another aspect, the invention relates to a polymerized and Preferably from about 25 t0 Higher p epoxy resin of high strength formed by contacting an tures result in faster reaction rates, but also can result in epoxy resin of the general formula shown above with a Production of more highly colored Pfuducts- In general, suitable curing agent. the condensation will require from about 5 minutes to In another aspect, the invention relates to a novel epoxy about 25 hours, depending in part upon catalyst and temresin of high strength formed by contacting p-xylylene perature employed.

glycol with an excess of an epihalohydrin selected from 0 Resins formed in accordance with the method described epichloroand epibromohydrin, preferably in the presence are post treated with an alkaline material to produce the of a Lewis acid catalyst. desired epoxy ethers. The reaction can be accomplished It is known in the art that the reaction of a polyhydric by adding the alkaline material directly to the reaction phenol with an epihalohydrin, such as epichlorohydrin, 40 mixture used in preparing the polymers, or the polymer results in the formation of an epoxy resin having a high can be recovered before it is combined with an alkaline content of pendant halomethyl groups. When cured, such material. Any of the known dehydrohalogenation materipolymerized epoxy resins have lap shear strength on als can be used in this reaction, such as sodium and aluminum metal on the order of 1000-1500 pounds per potassium hydroxides, sodium and potassium carbonates square inch. and bicarbonates, hydroxides of magnesium, zinc, lead, It is an object of this invention to provide a high iron, and aluminum, and the corresponding oxides, and strength epoxy resin which, when cured, has a lap shear the like. strength in excess of 2500 pounds per square inch. It is .The aluminates, silicates, and zincates of alkali metals, also an object of this invention to provide a high strength, such as sodium and potassium aluminates and sodium fire resistant epoxy resin which, when cured, has unusually and potassium zincates, are particularly good dehydrohigh utility as an adhesive and coating composition. halogenating agents when used in substantially, or com- Other aspects, objects, and the several advantages of pletely, non-aqueous media. this invention will be apparent to one skilled in the art The amount of dehydrohalogenating agent used can upon reading this disclosure and the appended claims. vary over a considerable range. However, in general, the In accordance with the invention, a composition of product produced should be reacted with enough alkaline matter comprisinga compound of the general formula material to provide at least one equivalent of effective 0 /O C z CH-CHz O(I]H-CHz OCH CH10-- OHg(|JHO- CHzCH- OH L crnoi L other is provided, wherein n is an integer of at least 1, preferably alkaline material, that is, one equivalent present after 1-3. When cured with a suitable curing agent, epoxy acidic catalyst has been neutralized, per halohydrin group. resins of the general formula shown above form adhesives Less than the equivalent amount of the alkaline material and coating compositions of unusually high strength. can be used if all the halohydrin groups are not to be .A method of forming the novel epoxy compounds of converted to the epoxy groups. this invention comprises contacting a xylylene glycol se- In most cases, the alkaline material can be applied to lected from ortho-, meta-, and para-xylylene glycols with the halohydrin as an aqueous solution or suspension or an excess of epihalohydrin selected from epichlorohydrin dissolved in an inert solvent, such as ethers, aliphatic, cyand epibromohydrin, preferably in the presence of a Lewis cloaliphatic and aromatic hydrocarbons, halogenated hyacid catalyst. drocarbons, and the like. If the above-noted aluminates,

silicates or zincates are used as the alkaline material, the dehydrohalogenation is preferably effected in an nonaqueous medium, and the salts per se are dissolved in organic solvents or diluents. carbon tetrachloride, 1,4- dioxane and bis(2-chloroethyl) ether are particularly satisfactory as solvents for this purpose.

The dehydrohalogenation reaction can be accomplished at temperatures which preferably range from about 20 C. to about 150 C., and more preferably, from about 25 C. to about 100 C. The dehydrohalogenation reaction is generally carried out for a period of about 5 minutes to about 8 hours, usually about minutes to about 4 hours.

At the end of the reaction period, the reaction mixture can be filtered through a suitable filtering medium, e.g., diatomaceous earth, to remove any alkali metal halide. The filtrate can then be treated to recover the epoxide. If the reaction has been conducted in the presence of water, care should be taken to avoid hydrolysis of the epoxide groups during the separation process. This can be accomplished by various extraction or distillation methods using subatmospheric pressures and conditions unfavorable to hydrolysis of the epoxide groups. Separation can be conveniently eifected by treating the aqueous reaction mixture in a continuous extraction apparatus wherein any suitable extractant such as ester, alcohol, ether, hydrocarbon, etc., may be utilized. The extracted epoxide can be separated from its solution with the extractant by subjecting the preferably anhydrous solution to distillation or other separation operation.

In the case where the reaction has been conducted in the absence of water, but in the presence of solvents, as is preferably the case with the above-described aluminates, silicates and zincates, the novel polyepoxy polyethers can be recovered by any suitable method, such as distillation, extraction, and the like. If no solvent or diluent is employed, the polyepoxide may be recovered and purified by any convenient method, such as distillation, solvent extraction, fractional precipitation, and the like.

For certain applications, such as in the preparation of surface coating, fibers or filaments, it is sometimes desirable to have products of still higher molecular weights. Such products can be obtained by reacting the above-described polyepoxys with polyhydric compounds. Polyhydric compounds used for this purpose may be any polyhydric alcohol or polyhydric phenols. Polyhydric phenols that may be used for this purpose include, among others, resorcinol, catechol, hydroquinone, methyl resorcinol, and polynuclear phenols such as 2,2-bis(4-hydroxyphenyl) prop ane.

The new polyepoxy materials of this invention and their higher molecular weight derivatives produced as shown in the preceding paragraph can be polymerized through the epoxy groups to form valuable polymeric products. They can be polymerized alone or with other polyepoxide materials in a variety of different proportions, such as, for example, with amounts of other polyepoxides varying from 5 percent to 95 percent by Weight. Polyepoxides that can be copolymerized with these new polyepoxides include, among others, glycidyl polyethers of polyhydric phenols obtained by reacting polyhydric phenols, such as bis-phenol, resorcinol, and the like, with an excess of chlorohydrin, such as epichlorohydrin in an alkaline medium; polyepoxide polyethers obtained by reacting an alkane polyol, such as glycerol and sorbitol, with epichlorohydrin and dehydrohalogenating the resulting product; polymers prepared from ethylenically unsaturated epoxides, such as allyl glycidyl ether, alone or with other ethylenically unsaturated monomers; and polyepoxide polyethers obtained by reacting a polyhydric alcohol or polyhydric phenol with any of the above-described polyepoxides.

A great variety of different curing agents can be employed in effecting the above-described homoand copolymerization. Such agents include, among others, carboxylic acids or anhydrides, such as oxalic acid and phthalic anhydride; Friedel-Crafts metal halides, such as aluminum chloride, zinc chloride, ferric chloride and boron trifluoride as well as complexes thereof with ethers, acid anhydrides, ketones, diazonium salts, etc.; phosphoric acid and partial esters thereof including n-butyl orthophosphate, diethyl orthophosphate and hexaethyl tetraphosphtae; amino compounds, such as triethylamine, ethylenediamine, diethylamine, diethylenetriarnine, triethylenetetramine, dicyandiamide and melamine; polyamide resins, e.g., from polycarboxylic acids and poly-amines, having readily replaceable hydrogen atoms; and salts of inorganic acids, such as zinc fluoborate, potassium persulfate, nickel fluoborate, copper fluoborate, selenium fluoborate, magnesium fluoborate, tin fluoborate, potassium perchlorate, cupric sulfate, cupric phosphate, cupric phosphite, magnesium arsenate, magnesium sulfate, cadmium arsenate, cadmium silicate, aluminum fluoborate, ferrous sulfate, ferrous silicate, manganese hypophosphite, nickel phosphate and nickel chlorate,

The amount of the curing agents employed can vary over a considerable range depending upon the agent selected. With curing agents having replaceable hydrogen, such as the amine agents, amounts of agent employed vary up to and including quantities sufiicient to furnish two replaceable hydrogen atoms for every epoxy group to be reacted. In most cases, satisfactory cures are obtained with amounts varying from 1 percent to 60 percent by weight of the material being polymerized, the amount of curing agent depending in part on the molecular weight of the curing agent and the number of replaceable hydrogen atoms in each molecule of the curing agent. With the phosphoric acid and eters, particularly preferred amounts vary from about 3 percent to 20 percent by weight. The other curing agents are preferably employed in amounts varying from 1 percent to 20 percent.

The curing is preferably effected by mixing the curing agent with the polyepoxide and heating the mixture, preferably at temperatures ranging from about 20 C. to 200 C. Solvent or diluents can be employed in the polymerization depending upon the intended application of the polymer and ease of operation of the polymerization reaction.

If the polyepoxides of the invention are to be used in the preparation of castings or pottings, the curing agent and the epoxy material are generally combined together and then poured into the desired mold or casting containing the electrical wires or apparatus and the mixture heated to eflect the cure.

The polyepoxides and their higher molecular weight derivatives can also be employed with the afore-described curing agents to prepare improved surface coating compositions of the air-drying or baking type. In utilizing the products for this application, it is generally desirable to combine the epoxy material and curing agent with the desired solvents, and if desired, other film-forming materials and driers, and then apply the resulting mixture to the surface to be coated. Film-forming materials that can be used with the epoxy material in this manner include the drying oils, such as tung oil, linseed oil, dehydrated castor oil, soybean oil, and the like; cellulose derivatives such as cellulose nitrate, cellulose acetate, cellulose acetate butyrate, cellulose propionate, ethyl cellulose, and mixtures thereof; and viny polymers, such as polymers of vinyl chloride, vinylidine chloride, methyl methacrylate, diallyl phthalate, and the like. The coatings prepared in this manner can be allowed to set to a hard finish at room temperature or heat can be applied to hasten the cure.

The new polyepoxides can also be employed with the curing agents to prepare valuable adhesive compositions. In utilizing the products for these applications, it is generally desirable to combine the liquid epoxy material alone or with other epoxy resins with conventional fillers and curing agents and then to use the spreadable fluid-as adhesive for materials, such as wood, plastic, metal, and the like.

In a particularly useful application, the new polyether time the temperature rose from 25 C. to 100 C. The polyepoxides are employed to impart self-extinguishing mixture was then stirred for an additional 40 minutes.

characteristics to laminates, particularly-paper laminates. The mixture was cooled to 80 C., and 23 g. of solid The new polyether polyepoxides can be combined with sodium hydroxide was added. The resulting mixture was conventional liquid polyepoxides, fillers and curing agents, stirred at 90100 C. for 2 hours, cooled, diluted with and in particular for the best flame resistant characterabout 500 ml. of a 50:50 mixture, by volume, of benzene istics SOI Il C antimony oxide will be added. The mixture is and acetone, and filtered. Evaporation of solvent from made up as a liquid, suitably by use'of a diluent such the filtrate, under vacuum, gave 127 g. of viscous liquid as a monoepoxide, e.g., allyl glycidyl ether, and the lamiresidue (Resin B) which was found by analysis to connate prepared in otherwise conventional, manner. 10 tain 58.0 percent carbon, 6.5 percent hydrogen, and 21.2 In another useful application, the new polyether is percent chlorine. This resin had a molecular weight of added inamounts from 5 to 50 percent "or more, based on .1450 and an epoxy value of 0.044 equivalent per hundred the total mixture, to composites of polyepoxides which grams. are expanded during cure by release of gases or vapors Samples of Resin A and. Resin B, described above, to form eellular resin foams. Use of the novel epoxies were each cured between aluminum metal strips, and the of this invention imparts flame resistanceto the resulting lap shear strength of the cured specimens was determined foams. ItJ-can also increase the flexibility of the foams. at 2 C- y the method of T 102 n e In addition, the new epoxy ethers can -be used as instance triethylenetetrarnine was used as the curing agent, stabilizing agents for various halogen-containing polyone equivalent, i.e., one-sixth mol, of the amine being mers, and particularly the vinyl halide'poly mers. These used for each equivalent of epoxide groups present in the products can be used as stabilizers, alone or in combinaresin used. In each instance, the curing was carried out tion with other stabilizing agents, such as urea and by maintaining the specimen for 16 hours at C., then thioureaderivatives. In most cases, the products are effor 8 hours at 70-75 C., and finally for 16 hours at 150 fective as stabilizers in amounts varying from about 1 C. The lap shear strength of Resin A, upon curing, was

percent to 5 percent by weight of the polymer being 25 found to be 3200 p.s.i., in contrast with the much lower stabilized; The epoxy material can be combined with the value of 483 p.s.i. found for the lap shear streng f halogen-containing polymer by any suitable method, such cured Resin B. Thus, the novel resin obtained through the as by dissolving the products in a suitable solvent or by use of p-xylylene glycol and epichlorohydrin was cured milling the products together on a suitable roll mill. to provide a product of far greater lap shear strength They can also be used as secondary plasticizers in comthan was exhibited by similarly cured resin obtained bination with plasticizers, such as dioctyl phthalate, and through the use Of P Py p and pithe like. I chlorohydrin.

The following example indicates the utility of the novel When Resin A was cured in the same curing cycle epoxy resins of the invention. with an amount of triethylenetetramine, 20 percent, 50 Example percent, and 100 percent greater than that used in curing the same resin as shown above, the lap shear strength p-Xylylene glycol and epichlorohydrin were used in of the cured specimens was 4500 p.s.i., 3700 p.s.i., and

the preparation of a resin within the scope of this in- 3100 p.s.i., respectively.

vention. To a 500 ml. resin flask were charged 69.1 g. When Resin A was similarly cured with a linear poly- (0.5 II'lO1)'p-Xylel'le-ll,a"dl()1 (p-xylylene glycol) and 230 40 amide resin (Versamid 140) derived from the condensag. (2.5 mols) epichlorohydrin. As the mixture was stirtion of a dimeric fatty acid with a polyamine substance red at 25 C., 4 g. boron trifluoride ethera'te was added and having an equivalent weight of 143, using 1.2.0 equivdropwise" during 1.5 hours. An exothermic reaction ocalents of polyamide for each equivalent of epoxide groups curred causing the temperature to rise rapidly to 75-80 in the resin, the lap shear strength of the cured specimen C. The temperature was maintained thereafter at 80-100 was 3340 p.s.i.

C. After the addition of catalyst was complete, the mix- A mixture consisting of a sample of Resin A containing ture was stirred for 2 hours at -75 F., treated with 52 1.20 equivalents of triethylenetetramine per equivalent of g. solid sodium hydroxide and heated at -90" C. for epoxide groups in the resin, and containing 15 weight per- 30 minutes. The mixture was cooled, diluted with 400 ml. cent of antimony trioxide based on the total weight of benzene, and filtered, and solvent was evaporated under 50 the mixture, was cured by maintaining the mixture for vacuum to give about 240 g. of a thick clear liquid 4 hours at 25 C., then for 16 hours at 70 C., and (Resin A). Based on analysis, the structure of the prodfinally for 4 hours at 140 C. The cured mixture was not was: placed in the flame of a burner until the mixture began I l CHzCl CHzCl o o 0/11}:HCH2 (OCHCH2) OCHT-CH20- CHRCH-O)CHECQBHZ An;aIysis.Calcd for C H O Cl percent C, 50.4; H, to burn. Upon removal of the burning mixture from the 6.2; O, 20.6; Cl, 22.8; mol wt., 620 epoxy value, 0.31 eq./ flame of the burner, burning of the mixture quickly g. Found: percent C, 51.8; H, 6.2; O, 20.5; C1, 21.7; ceased, thus demonstrating the good fire resistance of the mol wt., 558; epoxy value, 0.32 eq./100 g. mixture.

For comparative purposes, a resin outside the scope of 65 Reasonable variation and modification are possible this invention was prepared through the use of 4,4'-isowithin the spirit and scope of the foreging disclosure and propylidenediphenol. To a mixture of 57 g. (0.25 mol) the appended claims to the invention, the essence of which 4,4-isopropylidenediphenol and g. (1.25 mols) epiis a composition of matter having the general formula .Jn L n chlorohydrin was added, with stirring, 2.2 g. boron trifluoride etherate over a period of 1 hour, during which 75 wherein n is an integer of at least 1.

7 W s I claim: 1. A compound having the general fourmula C 1- 0H0H-00H0HJ00H CHzO 0HzOHO OHg-Cfi CHg L 2311,01 .-In L (Emmi wherein n is an integer of at least 1. 0 I References Cited 2. The amine or polyamide resin cured compound of UNITED STATES PATENTS claim 1. 2,898,349 8/1959 Zuppinger et a1. 260-348 3. The cured compound of claim 2 wherein the amine I $096,349 7/ 1963 Meyer et v t is triethylenetetramine and the polyamide resin is derived 15 FOREIGN PATENTS from a dimen'c fatty acid with a polyamine. 676,308 12/1963 Canada; a

4. The cured product of claim 3 further comprising WILLIAM H SHORT P -i Examiner i antimony trioxid- 0 T. PERTILLA, Assistant Examiner 5. The compound of claim 1 wherein n is an integer of Us CL v I 

